[LL FIR] extract shortening rendering for tests to a separate file

So it can be reused from other tests

^KT-57966 fixed

analysis/analysis-api-impl-base/tests/org/jetbrains/kotlin/analysis/api/impl/base/test/cases/references/AbstractReferenceShortenerTest.kt

@@ -6,6 +6,7 @@
 package org.jetbrains.kotlin.analysis.api.impl.base.test.cases.references
 
 import org.jetbrains.kotlin.analysis.api.components.ShortenOption
+import org.jetbrains.kotlin.analysis.api.impl.base.test.cases.references.ShorteningResultsRenderer.renderShorteningResults
 import org.jetbrains.kotlin.analysis.test.framework.base.AbstractAnalysisApiBasedSingleModuleTest
 import org.jetbrains.kotlin.analysis.test.framework.services.expressionMarkerProvider
 import org.jetbrains.kotlin.analysis.test.framework.utils.executeOnPooledThreadInReadAction
@@ -36,16 +37,7 @@ abstract class AbstractReferenceShortenerTest : AbstractAnalysisApiBasedSingleMo
             shortenings.forEach { (name, shortening) ->
                 appendLine("with ${name}:")
                 if (shortening.isEmpty) return@forEach
-                shortening.getTypesToShorten().forEach { userType ->
-                    userType.element?.text?.let {
-                        appendLine("[type] $it")
-                    }
-                }
-                shortening.getQualifiersToShorten().forEach { qualifier ->
-                    qualifier.element?.text?.let {
-                        appendLine("[qualifier] $it")
-                    }
-                }
+                renderShorteningResults(shortening)
             }
         }
         testServices.assertions.assertEqualsToTestDataFileSibling(actual)

analysis/analysis-api-impl-base/tests/org/jetbrains/kotlin/analysis/api/impl/base/test/cases/references/ShorteningResultsRenderer.kt

@@ -0,0 +1,28 @@
+/*
+ * Copyright 2010-2023 JetBrains s.r.o. and Kotlin Programming Language contributors.
+ * Use of this source code is governed by the Apache 2.0 license that can be found in the license/LICENSE.txt file.
+ */
+
+package org.jetbrains.kotlin.analysis.api.impl.base.test.cases.references
+
+import org.jetbrains.kotlin.analysis.api.components.ShortenCommand
+
+internal object ShorteningResultsRenderer {
+    fun StringBuilder.renderShorteningResults(shortening: ShortenCommand) {
+        if (shortening.isEmpty) {
+            appendLine("EMPTY_SHORTENINGS")
+            return
+        }
+
+        shortening.getTypesToShorten().forEach { userType ->
+            userType.element?.text?.let {
+                appendLine("[type] $it")
+            }
+        }
+        shortening.getQualifiersToShorten().forEach { qualifier ->
+            qualifier.element?.text?.let {
+                appendLine("[qualifier] $it")
+            }
+        }
+    }
+}